Archive for the ‘Criticism’ Category

EDIT 12-12-11 I encourage you to read the comments at the end of this post, including one by Neil deGrasse Tyson himself! Based on some of the constructive comments and criticisms I’ve gotten here and on Facebook, I’m backing off on the average criticism a bit, but I am leaving it in the post for the purpose of integrity and not pretending like I didn’t say something I did say.

Some of my friends and I went to see Neil deGrasee Tyson speak at SIUE last night (12-7-11). His talk was verysomewhat similar (~25% the same) to his keynote address given at TAM 9 from Outer Space last July, and he made a couple of statements (one of which was repeated from TAM9) that I thought were worthy of a little Cordial Deconstruction.

I know it seems disingenuous to preface a criticism of someone by stating how much you like them, but I’m still going to preface this with the statement that I’m a big fan of Neil deGrasee Tyson, and relish every opportunity to hear him speak, but I did have problems with a couple of the things he said last night.

An Average Mistake

Dr. Tyson went through a series of slides showing statements made by various people that demonstrate a lack of understanding of science and or mathematics, but his criticism of one of the statements was not very well thought out, in my opinion. I don’t remember the exact quote, but the essence of the statement was “half of all students are below average”, and Dr. Tyson’s criticism was that this statement was so definitively self obvious as to not require stating. He said that it was kind of the whole point of average, and that half of any sample would always be below average since average represents the middle. I know Dr. Tyson understands the concepts of median, mean, and mode, but in spite of that, he apparently didn’t think through his criticism of the statement in that slide. He made the same point at TAM9, and he apparently hasn’t revised it since then. It’s just not correct to say that half of any set will always be below average.

Before I can go any further, we have to determine what someone means when they say average. The most common use of that term is in regards to the arithmetic mean, which is when you add up all the values and divide by the number of values.

I’ll use a simple hypothetical situation with math simple enough to be done without a calculator. Let’s say I administer a ten question exam to ten students. Nine students score a perfect 10, and one student scores a perfect 0.

The mean score is 9 ((9*10+0)/10). In this example using mean for average, 1 student (10%) of the sample scored below average, and 9 students (90%) scored above average.

Sometimes, one might be referring to the median value when they use the term average.

From Wikipedia:

“Median is described as the numerical value separating the higher half of a sample, a population, or a probability distribution, from the lower half”

By definition would seem to fit Dr. Tyson’s statement.

However, I see two problems here. Firstly, while it may not be technically incorrect to intend median when referring to the average value, the typical understanding of what is meant by average is the arithmetic mean. In my opinion, in order to avoid confusion, the use of the word average with general audiences should usually be restricted to refer to the arithmetic mean, and one should say median when they mean median.

The other problem is that even median doesn’t always result in half of a given sample being below average.

Also from Wikipedia:

“At most, half the population have values less than the median, and, at most, half have values greater than the median. If both groups contain less than half the population, then some of the population is exactly equal to the median.”

In the above example, when following the rules used to determine the median value, it comes out to be 10. Using median for average, 10% of the students are still below average, while 90% are average, and nobody is above average.

There are other things that one could intend when using the term average, such as mode, but these uses would be even more uncommon and really need to be specified when intended.

Initial Mistake

Dr. Tyson also made what in my opinion, was an even grosser misstatement regarding the New Horizons probe to Pluto and the Kuiper Belt. (To clarify, it was unquestionably a factual misstatement; it is my opinion that the severity of this misstatement is larger than that of his comment about averages.)

He stated that New Horizons was the fastest thing we had ever sent anywhere, and it would eventually overtake the Voyager probes as the most distant man made objects from the Earth. This is factually incorrect, though there is a grain of truth at the heart of this statement.

While it is true that the New Horizons probe achieved the highest launch velocity of any craft so far, left Earth faster than any other mission or probe, and had the highest initial solar escape trajectory, it neither has the record for highest maximum velocity (the Helios probes hold that distinction), nor is it traveling faster than Voyager 1. While New Horizons had a higher initial velocity than Voyager 1, Voyager’s velocity was boosted by gravitational slingshots with outer planets to a higher final velocity than New Horizon’s, and New Horizons will never overtake Voyager 1 as the most distant man made object form the Earth (or Sun).

Footnote Acknowledgement of Personal Fallibility

Normally, when I Deconstruct something, I like to be able to review it several times, so I can be sure my Deconstruction is valid, and I am not missing something that would invalidate my criticisms, but the talk last night was live, I can’t review a video of it, and I didn’t take any notes. (Notes would only help me remember things I noticed at the time and would not allow me to look for things that I may have missed anyway.) As a result, this post was written based on my recall and understanding of what Dr. Tyson said last night (and last July), and is therefore subject to various limitations that could leave me in error in regards to my Deconstruction of the two points discussed in this post. I therefore acknowledge the possibility that I may have misheard, misunderstood, or improperly recalled the points put forth by Dr. Tyson, and I could be off base on one or both of my criticisms, which is one of the reasons why I allow commenting on my posts, and I invite any relevant commentary anyone might have to add.

“Ok, you seem to have completely missed the point here. The point of Schrodinger’s cat is precisely about quantum probability, which you have stated, and you seem to have a knowledge of this thought experiment and what it means. The thing that is really getting to me is the fact that the point is still being made in almost exactly the same way, but you are quibbling over the fact that it is not explained fully and mentioned the radioactive isotopes and the Copenhagen interpretation. Surely a 10 minute conversation about this thought experiment would waste time in the programme and really doesn’t matter. The nitty gritty stuff is for scientists, not for people just watching some action on television. Don’t get me wrong I love reading physics as much as any studious person, but it really doesn’t matter in the slightest that he didn’t go into every single little detail regarding the experiment. Stop wasting your time complaining and read more physics, you’re obviously interested in it. Not only that but you’ve wasted my time having to correct your ignorance.”

What follows is my reply to that comment, which I felt was worthy of it’s own post.

It would appear to be you who has completely missed the point and demonstrated your ignorance on the topic. By substituting a poisoned sardine for the decay of a radioactive isotope, quantum probability has been eliminated from the thought experiment and has been replaced by a regular non-quantum, deterministic event.

Further, when the physicist states that the observer gets to choose whether the cat is alive or dead, that is not quantum physics and the collapse of the quantum waveform, it’s a philosophy of a post modernist subjective reality, dependant on the perception and will of the observer. In quantum mechanics, the observation of the cat in the original thought experiment collapses the quantum waveform and solidifies the current state of the cat; it does not choose which state the cat is in, which is what the physicist in the TV show said.

The writers completely misunderstood the thought experiment, and got it wrong on two key points. They replaced a quantum probability with a deterministic event, and then gave the observer a choice in the end state of the cat rather than the observation only being a choice to create the end state of the cat with no ability to choose what that end state was.

It is acceptable to boil a scientific concept like quantum probability and decoherence down to a form the average TV viewer can understand, but only if it remains relatively accurate in the key points.

I have not wasted my time at all, and if you have wasted you time is not my fault. It would seem that I have either read more physics than you, or I have at least better understood and appreciated the nuances of what I have read. It also seems that you either failed to pay attention while reading my post, or you were unable to understand they key points of my post. If by reading this reply you better understand the key points as to why the writers got the thought experiment wrong, then you have not wasted your time at all either.

And by the way, you’ve spelled your name wrong if your intention was to say “you’re wrong” rather than talk about a wrong that I posses. I normally don’t quibble about simple spelling mistakes, but I would think if someone takes the time to compose a 181 word statement claiming someone is wrong on a matter of quantum physics, that they would take time to make sure they haven’t confused “your” with “you’re”. Such a mistake hardly adds to your credibility.

Recently I came across an article on space.com, Study: If We’re Not Alone, We Should Fear the Aliens by Mike Wall, SPACE.com Editor, that I thought was deserving of some Cordial Deconstruction. Technically, this is more a Deconstruction of the study the article was reporting on, and not so much of the space.com article, though I may refer to the two interchangeably in this post.

The article makes the following statement which it describes as the only two possibilities based on the study:

“When considering the prospect of alien life, humankind should prepare for the worst, according to a new study: Either we’re alone, or any aliens out there are acquisitive and resource-hungry, just like us.”

I’ll first deal with the assertion that we are probably alone. It would only take one other example of a planet with intelligent life in the approximately 300 sextillion (30 X 10,000 billion billion) stars in the visible universe for this assertion to be wrong. The fact that we have not heard from ET is not reasonable support for the assertion that not even one single ET existst. There are numerous possible reasons why we might not have heard from ET yet, other than ET doesn’t exist (though that is a possibility). Among those possible reasons are the following:

-It’s possible ET’s civilization didn’t stay at the level where they leaked radio signals into space long enough. (Fiber optics, directed digital broadcasts, and beyond anyone?)

-It’s possible that ET is so far away that there hasn’t been enough time for its signals to reach us yet.

-It’s possible that ET’s civilization is too far away for their leaked signals to be discernable from background noise.

-It’s possible that ET evolved on a planet that wasn’t conducive to developing technology. Maybe the requirements for life are there, but there aren’t enough heavy metals to develop technology beyond the Stone Age level. Maybe the environment is so hostile that ET is just barely able to survive and doesn’t have time to develop beyond the Stone Age. Maybe it’s a water world of whale like creatures. (Our whales haven’t developed radio technology despite a lack of serious interference from humans until a few hundred years ago.)

Really, at this point the only conclusion that we can come to from the fact that we have not yet detected ET is that if ET exists, it is not an easy thing to detect ET.

As a footnote, I’ll mention that there are at least two other possible reasons why we may not have heard from ET:

-It’s possible that ET died out before developing radio technology, either due to natural events or self destruction.

-It’s possible ET’s civilization didn’t last long enough to be detected.

Though both would support the idea that we are currently alone, they lead to another possibility- Even if we do detect signals from an extraterrestrial intelligence, considering that they will have likely originated a very long time ago (anywhere from thousands to billions of years ago), ET may have died out since transmitting the signals, and thus we could technically currently still be alone despite the signal. In the absence of an actual visit by ETs, we can’t actually know if there are currently any other intelligent civilizations light years away. Even with a visit from ET, they can’t know if their civilization still exists back on their home world, signals and information can’t travel faster than the speed of light.

One very astonishing assertion by the article/study is that evolution is predictable, and that it inevitably leads to intelligent civilizations.

“Further, Conway Morris says, evolution operates predictably, producing relatively predictable outcomes. These two suppositions argue that alien life, if it exists, should be fairly similar to terrestrial life, generating intelligent beings much like us”

It’s very astonishing because life existed on this planet for about 3.7 billion years before a species came along that could fashion simple stone tools, let alone broadcast electromagnetic signals such as radio. For 99.9% of the time that there has been life on this planet, there has been no species that comes close to the study authors’ definition of intelligent. Multicellular didn’t appear on Earth until after about 2 billion years after life first developed, and vertebrates took about 3.2 billion years to show up. Dinosaurs roamed the Earth fat, dumb, and happy for about 160 million years and may have stayed that way if they hadn’t been killed out in a mass extinction. Seeing as we have only one example of a planet with life on it to use as a reference, I think it’s incredibly anthropic and near sighted to conclude intelligent beings are always the inevitable result of evolution.

The article quotes Conway Morris, one of the authors of the study, regarding the ability to contact alien civilization despite the probable vast distance between them,

“At least so far as this galaxy is concerned, a distance of circa 100,000 light years doesn’t seem insurmountable, given a relatively slow diffusion rate and a geometrical rate of establishment of colonies,”

Ignoring the possibility that intelligent life could be as rare as one civilization per galaxy (we really have no idea how rare or common intelligent life may be outside the sailor system) as Morris does, that’s an interesting use of the word “given”. Normally, I would reserve the word given in such a context for either an established fact or a reasonable assertion. In this context the word would be better replaced with the word “assuming”. There is no reason to assume a geometrical rate of establishment of colonies or any interstellar colonies at all. I’ve previously shown in a series of posts that there’s no point in worrying about an alien invasion, partly because the resource requirements of interstellar travel make such travel and alien invasion highly impractical. Simply put, the energy and resource requirements for interstellar travel vastly outweigh any possible returns. If you have the resources to travel to another star to plunder one of its planet’s resources, you don’t need to do so. By analogy, why drive from Florida to Alaska to buy gas for your car? If you have enough gas to drive to Alaska, you don’t need to go. The numbers don’t add up. This concept is covered more in depth in posts on the linked page.

The other reason to not worry about an alien takeover is that, assuming I’m wrong, we’re doomed anyway, as I also concluded in a post in the above link. If ET is so advanced and capable that it can travel across the stars (perhaps superluminally) without bankrupting their planetary economy, then they will find us and do as they please no matter how hard we try to hide or prepare, and our puny bullets and nuclear weapons likely won’t bother them at all.

Don’t worry, be happy, because worrying won’t matter one way or another. :)

Like this:

In case you’re not aware, NPR fired Juan Williams after he made some anti-Muslim remarks on the Bill O’Reilly show on Fox News. Probably the most significant statement he made was the following:

“But when I get on a plane, I got to tell you, if I see people who are in Muslim garb and I think, you know, they’re identifying themselves first and foremost as Muslims, I get worried. I get nervous.”

I’m not going to discuss what I think of what Williams said, and I’m not going to discuss whether or not I agree with NPR’s decision to terminate his employment with them.

I am going to discuss some of the reactions to NPR’s decision. In this post on the Fox News web site, numerous people are crying censorship and are demanding an end to federal funding of NPR.

Here are a couple of quotes from the article:

Newt Gingrich:

“… the idea that that’s the excuse for National Public Radio to censor Juan Williams is an outrage and every listener of NPR should be enraged that there’s this kind of bias against an American,”

Mike Huckabee:

“NPR has discredited itself as a forum for free speech and a protection of the First Amendment rights of all and has solidified itself as the purveyor of politically correct pabulum and protector of views that lean left,”

Let’s be clear here. NPR has a right to determine who they want to employ and who they want to represent them. NPR is not obliged to provide Juan Williams a venue on which to appear anymore than they are obliged to provide one to me. NPR is not preventing Juan Williams from appearing on Fox News or anywhere else; he is perfectly free to speak his mind anywhere someone will give him a microphone. NPR has not violated Juan Williams’ First Amendment rights in any way. NPR is not a public access soap box that every American has a right to utilize. Is NPR violating my First Amendment rights by preventing me from using NPR to broadcast my insights? No, clearly not, and neither are they violating any First Amendment rights of Juan Williams. I am not constitutionally entitled to a job as an on air personality at NPR, and neither is Juan Williams.

Let’s all be clear and honest here. If you object to NPR’s decision, fine. If you object to the continued federal funding of NPR, fine. Go ahead and campaign to end their funding, but don’t do so on the invalid argument that NPR is engaging in censorship or the suppression of free speech. That demonstrates either an ignorance of the First Amendment and censorship or intentional dishonesty: you either don’t understand the concepts, or you are lying to better sell your position to the ill-informed.

I believe Bill O’Reilly believes in what he says. When he recently said, “Muslims killed us on 9/11“, I believe that he believes that we were attacked by the Muslim religion itself (ie: we were attacked by the Muslims) rather than just that the persons who carried out the attack were Muslims.

I also believe he is dead wrong. Though it is technically correct to say that 9-11 was carried out by Muslims, it is also technically correct to say 9-11 was carried out by heterosexual men. In either of these cases, the statements serve no useful purpose and only serve to deceive and mislead by making false implications and encouraging erroneous inferences about responsibility for the attacks. As a heterosexual man who did not participate in the attacks, I wish not to be incorrectly associated with those that did, and I imagine many Muslims feel the same way.

I could provide various statements about things that were done by (people who happened to be) Republicans or Christians that I’m sure Bill O’Reilly would freak out about if you said them to his face, but I think I’ve already made my point.

Like this:

Astronomers have spotted a so-called Goldilocks planet ( Gliese 581g)orbiting another star. A goldilocks planet is a one that is of the right size to be terrestrial and which lies in the habitable zone of its parent star; conditions which are needed to support life remotely close to as we know it.

During a press briefing, astronomer Steven Vogt, professor of astronomy and astrophysics at the University of California, Santa Cruz said the following:

“Personally, given the ubiquity and propensity of life to flourish wherever it can, I would say, my own personal feeling is that the chances of life on this planet are 100 percent,”

“I have almost no doubt about it.”

This is an astounding statement for any reasonable scientist to make, even one that is an astronomer and not a biologist. I would even say such a statement borders on irresponsible, assuming there isn’t some missing context or qualification to that statement. Professor Vogt is essentially saying that the fℓ term (the fraction of the habitable worlds that actually go on to develop life at some point) from the Drake Equation is 100%, which is extraordinarily unlikely to be true.

Whether or not already developed life flourishes everywhere we look on earth is independent from the likelihood of it developing in the first place. By analogy (admittedly one of the weakest forms of argument), diesel fuel is very hard to light on fire, but burns very well once started.

We really don’t have any reasonable estimate for the fℓ term of the Drake Equation, but I think we can say is significantly less than 100%. If it were 100%, you would expect life to be spontaneously developing all the time. You would expect to be able to observe spontaneous abiogenesis at least under laboratory conditions, and yet, we have not yet ever observed life arising from non-life, therefore it must be somewhat less than common.

Additionally, this planet may be the most habitable world we’ve found so far, but the Garden of Eden it ain’t. First of all, it orbits a red dwarf star, which isn’t ideal. Red dwarf stars are fairly deficient in UV radiation which is probably important to, and may be vital for, the development and evolution of life. Also, the planet is tidally locked with its parent star, meaning one side of the planet is always facing the star and one side is always in darkness- not ideal for moderate temperatures on most of the planet. It’s likely the planet itself would have a Goldilocks zone of its own; the day side is probably too hot, the night side is probably too cold, and the zone bordering the day and night zones is probably the habitable zone of the planet.

Even if my last paragraph regarding the actual habitability of the world in question is totally wrong, even if this planet existed in exactly the same conditions as the Earth in regards to parent star, orbit, composition, magnetic field, etc, there’s just no reason to assume a 100% chance of life. By definition, that would mean life had to instantaneously spring up the moment habitable conditions were achieved, and that life would continue to spontaneously arise all the time. I personally believe (without much supporting evidence) that the odds of life developing in any ideal environment are probably very low, but I will confidently say the odds are significantly less than 100%, and they are less for Gliese 581 g than they were and are for Earth.

Like this:

I have to work tonight and was sick Sun-Tue, so I probably won’t get a real post out this week, but I’d like to take a moment and say the following:

Book burning is not a way to demonstrate that you are educated or enlightened, and it is certainly not a way to demonstrate your moral superiority.

Don’t just oppose it because it may put American military personal at risk.

Don’t oppose it because you feel all holy books should be respected. I don’t have to respect anyone’s holy book if I don’t want to. I only have to respect someone’s right to have a holy book. I’m perfectly free to ridicule that book, and I’m also free to ridicule them for holding that book holy while I’m at it if I want to be dickish about it.

There are better and more complete reasons to oppose this planned act of bigotry and hate.

The following posts by PalMD are a small sample of the numerous excellent posts out there on the internet regarding the planned burning of a bunch of Qurans this Saturday by a Florida pastor. Please take time to read them.

Like this:

I’d like to Cordially Deconstruct just a couple of items from and article I read today titled, “Cars: The next hacking frontier” by Elinor Mills. The article is about the potential of hacking in today’s increasingly computerized and networked automobiles. It’s generally a decently written article, but there’s a couple points I want to address. The first is statement from a report by a team that managed to hack a wireless tire pressure monitoring system of a vehicle. The article author included the following quote from the report:

“While spoofing low-tire-pressure readings does not appear to be critical at first, it will lead to a dashboard warning and will likely cause the driver to pull over and inspect the tire,” said the report. “This presents ample opportunities for mischief and criminal activities, if past experience is any indication.”

Listen, I don’t dispute that the lack of security in the TPMS displays a seriously concerning lack of attention to the concept of wireless communication security by automotive system designers, but I think the study is over blowing the seriousness of this particular vulnerability to make their point. I seriously doubt that many drivers would pull over if this light displays on their dashboard. Most drivers don’t even know what the light means. I certainly dispute the notion that it “will likely cause the driver to pull over and inspect the tire”. 46% of people surveyed didn’t even know the icon was supposed to be tire treads, and anyone who knows what the indicator is will likely know they don’t need to worry about it until they get to a service station. Every time it gets cold, the pressure in my tires decreases in accordance with the ideal gas law, and the indicator lights up on my dashboard. If my experience is remotely typical, many drivers with cars new enough to have the indicator are already accustomed to ignoring it until they have a convenient moment to deal with it, and certainly wouldn’t pull over right away to inspect their tires.

The article then goes on to mention another report where researchers

“tested how easy it would be to compromise a system by connecting a laptop to the onboard diagnostics port that they then wirelessly controlled via a second laptop in another car.”

Surprise, they were able to control all sorts of computer controlled functions like the anti-lock brakes, engine computer, speedometer display, etc. The article author concedes,

“Granted, the researchers needed to have physical access to the inside of the car to accomplish the attack. Although that minimizes the likelihood of an attack, it’s not unthinkable to imagine someone getting access to a car dropped off at the mechanic or parking valet.”

OK, and it’s also possible they could plant a GPS tracker, wireless microphone, or bomb in your car, or cut the brake lines and cut a notch in your fan belt as well if they have physical access to the vehicle, all without touching the car’s computer or network system, what’s the point? The real security concern is the wireless (hands off) vulnerability; just stick with that topic, please.

One area where I think the article author actually underplays a concern is when she writes,

“The threat is primarily theoretical at this point for a number of reasons. First, there isn’t the same financial incentive to hacking cars as there is to hacking online bank accounts.”

Actually, there is a financial incentive in hacking cars; if you could successfully hack a GM car’s On Star system, you could potentially not only disable the alarm, but also unlock and start the vehicle and disable the ability of GM to track and disable the vehicle via On Star, so there’s a minor fail in the other direction for the article.

It was a generally well written article, but a few points were a little sub par. It may seem like nitpicking, but I usually feel that stretching points and using unnecessary hyperbole to enhance an article degrades the overall quality of an article, and I needed something to blog about today.

Like this:

While I drive to and from work each weekday, I listen to the local NPR affiliate, KWMU, a generally excellent source of broadcast news. During my drive home from work today, I caught a story on an outbreak of a diarrheal illness, crypo in some St. Louis county day care centers. The report mentioned that crypto is short for cryptosporidiosis and explained that cryptosporidiosis was a bacteriological illness spread through contact with infected feces, usually in swimming pools and day care centers. The same story was reported on the Post dispatch web site with virtually identical information. (The story broadcast on KWMU may have even credited the Post Dispatch for the story, but I didn’t catch it.) The PD story stated:

“The bacterial illness, cryptosporidiosis, is spread through contact with infected feces, most commonly in swimming pools and day care centers.”

The problem with the story as reported by both KWMU and the PD is that cryptosporidiosis is not a bacterial illness, and Blythe Bernhard, the author of the Post Dispatch article, could have learned that with a few seconds of fact checking on the internet. (See also the CDC’s site if you don’t trust Wikipedia.) Cryptosporidiosis is instead a parasitic infection caused by a protozoan parasite, Cryptosporidium.

I know this because some years ago I saw an episode of (I believe) Forensics Files regarding an outbreak of cryptosporidiosis in Milwaukee after a rainstorm caused untreated sewage to overflow the sewage treatment system and spill into the same water source a water plant got its municipal water from; an outbreak of cryptosporidiosis was the result.

As soon as I got home, I rushed to the computer to confirm my knowledge because no mater how sure I am of something, I like to be able to confirm and support my position; I try not to assume that I recall something correctly, even though in this case I was sure cryptosporidiosis was parasitic in nature and not bacteriological.

It’s not a major gaff per se, but neither was it in any way difficult to research either. Cryptosporidiosis is not bacterial and cannot be treated like a bacterial infection. In fact, there really is no treatment for cryptosporidiosis other than supportive care (you just have to let your immune system fight it off). In immunocompromised individuals, it can become a lifelong, chronic condition that can also be fatal. One would think the reporter would have looked up cryptosporidiosis to get more information on the disease. Sure it was just a quick, breaking news blurb, but

A. wouldn’t it be good to be sure you have the facts straight BEFORE publishing,

and

B. wouldn’t it be good to have some background info on the disease in case the story gets bigger and you have to revisit it?

As of 7:30PM local time, the story on the PD website has not been updated, which tells me nobody has gone back to check the facts after getting the breaking news published to the web, although someone did post the diarrhea song in the comments section. :)

UPDATE 8-26-10

As of 9:00AM the next day, the story on the PD website is still unchanged, though the diarrhea song has been deleted from the comments, and someone else posted a comment regarding cryptosporidiosis not being bacterial in nature. However, the story was repeated on the air on KWMU this morning, this time without any mention of a bacterial nature. Maybe KWMU actually read my E-Mail.

EDIT II 8-26-10

Apparently the PD website put out a nearly identical replacement article omitting the bacterial infection part, but left the original article in place for some reason. Maybe he app they use to deploy breaking news stories does not allow edits after publishing.

ne = the average number of planets that can potentially support life per star that has planets

fℓ = the fraction of the above that actually go on to develop life at some point

fi = the fraction of the above that actually go on to develop intelligent life

fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space

L = the length of time such civilizations release detectable signals into space.

For the sake of argument, let’s assume the equation itself is basically sound, tough that’s debatable. In that case, the accuracy of the number we can get from this equation depends on how accurate the values we plug into the individual terms are, so let’s look at the terms and see how well we can estimate those numbers.

The first term, R*, we have an OK, better than order of magnitude estimate for, so we’re off to not too bad a start, understanding that we’re not looking for a terribly precise value here.

For the second term, fp, we really don’t have a good number for right now. PZ says we have “growing evidence of values” for this number, and that’s not an inaccurate statement, as long as you understand that the evidence is not quite ripe for picking yet. While we have been making a lot of progress in detecting extra solar planets, we’re still only good at detecting larger giant type planets like Jupiter orbiting stars similar to the sun (the Kepler mission may change that). Because the best way we have to detect planets right now is to detect the wobble the planets induce in their parent star while they orbit, it’s easier to detect planets with a large mass relative to its parent star. Because of this, we haven’t yet been able to detected any planets of less than several Earth masses, which means what we currently have for this number is really a lower limit for this value, but we really don’t have a good estimate for an upper limit because we don’t know how many stars have only relatively low mass planets and no planets large enough to induce a noticeable wobble. We’re only on the second term, and we already have a little problem, but as long as we use the lower estimate for this values, we should be OK.

For the third term, ne, we really have nothing but projections using our solar system as a model. We don’t know how many rocky planets or moons are out there, we don’t know how many of them lie in the habitable zone of their parent stars, we don’t know how many of them have the right elemental composition, we don’t know how many have relatively circular orbits (to avoid extreme temperature variances), etc, etc. Even if we get better at detecting terrestrial planets, there are so many factors that contribute to the suitability of a planet for supporting life, many of which will be very difficult to detect, that it will be problematic to ever come up with a good value for this number.

As little as we have to go on for the third value, we have basically jack nothing to go on for the all the remaining terms. We have absolutely no clue about any of those numbers and any attempt to make an estimate for any of them is just wishful thinking or anthropically derived values by people wanting to find an answer.

What fraction of the unknown number of habitable worlds actually develop life? How does one even make up a number for this and keep a straight face? Without knowing how life arose here on Earth, how can we begin to say how probable it is anywhere else?

What fraction of the planets from the previous term develop intelligent life? Again, who knows? Our sample of 1 doesn’t give us much to go on. If the dinosaurs hadn’t died out, would we have intelligent dinosaurs now? Who knows? We assume we are the natural, logical conclusion of the evolutionary process because we’re here, but we could be an aberration, an exception to the norm.

What fraction of civilizations develop technology that releases detectable signals? It might seem reasonable to suggest that if they survive, that this is an inevitable outcome, but we shouldn’t be overly anthropic and assume we are the norm. We really don’t know. We do know that when Europeans ventured forth and explored the word, they ran into a lot of pre-industrial and stone age civilizations several millennia behind them technologically. We can’t even say if the native Americans would have ever developed technology in America under very similar conditions to what the Europeans had let alone say what would be likely on a planets of different conditions and abundances of resources.

How long do such technological civilizations release detectable signals into space? We haven’t stopped yet, so we don’t even have an anthropic reference number to go on here.

Frankly the best evidence we have for estimating a number for N is the lack of evidence so far. This is basically the Fermi Paradox. The Fermi paradox is the apparent contradiction between high estimates of the probability of the existence of extraterrestrial civilizations and the lack of evidence for, or contact with, such civilizations. I would say that this is not so much a paradox as an indicator that the estimates for N are probably unreasonably exaggerated. N must be low enough that we’re not currently detecting signals from alien civilizations. If they’re out there, we can at least say they’re probably not close by or we’d have detected them by now, which means alien civilizations probably aren’t as widely dispersed as the optimists project.

Honestly I’m amazed that anyone tries to invoke the Drake equation, given that we can only reasonably speculate the value for N is between 0 (if you don’t count us) and millions or even billions. I automatically loose a little respect for any scientist who seriously invokes the Drake equation; the equation is junk science and probably always will be.